The present invention relates to an electromagnet having an armature.
Known electromagnets having an armature are used, for example, in solenoid valves of pressure-regulating valves for injection systems of internal combustion engines. Such solenoid valves have electrical connector elements, which are led from a side of the armature opposite the electromagnet, through an opening of the armature plate, and are contacted to the solenoid coil. In order to prevent the connector elements from coming in contact with the inner wall of the armature-plate opening upon activation of the electromagnet, and impairing the movement of the armature plate through friction, the known electromagnets have mechanical adjusting arrangement in the form of a guide pin and a groove in the armature plate that interacts with the guide pin, the adjusting arrangement adjusting the armature plate to a predetermined angle of rotation and preventing the armature plate from rubbing against the electrical connector elements of the solenoid coil. However, it is disadvantageous that the mechanical adjusting arrangement can impair the movement of the armature.
The present invention""s electromagnet having an armature eliminates the disadvantages associated with the use of mechanical adjusting arrangement. When a current acts on the solenoid coil, at least one cutout in the armature plate and a second opening in the pole face of the magnet core, which is assigned to the first opening, allow magnetic forces to adjust the armature plate to a predetermined rotational position, in which, for example, the connector elements pass through a cutout of the armature plate without touching it. Therefore, one may advantageously dispense with the design of mechanical adjusting arrangement that are expensive to manufacture. The stray magnetic flux in the region between the inner-wall segments of the at least one cutout and the at least one second cutout advantageously creates a frictionless design of the armature plate and the armature. In the case of a minimal rotation of the armature plate about the armature pin, restoring forces, which act on the armature plate and drive the armature back into its predetermined rotational position, result from the nonuniformity of the magnetic field.
The present invention introduced here may advantageously be used in pressure-regulating valves, in order to prevent frictional losses of the armature and impairment of the closing operation of the solenoid valve. In addition, the present invention may also be used in solenoid valves for injection valves of internal combustion engines, where the armature is adjusted in order to, for example, keep the cross-section of the fuel discharge channels running through cutouts of the armature from narrowing in response to rotation of the armature. However, the present invention is in no way limited to use in solenoid valves, and may be used in all electromagnets having an armature, where an armature plate, which is supported so as to be able to slide and rotate, has to be adjusted to a preferred angular position.